Yeah, generally speaking UPS is still running a pretty great operation in Commerce City (both air and ground sort for nearly anything delivered in the state, although Grand Junction will occasionally do some sort for us Western Slope yokels for Ground packages when the situation is just right [e.g. the feeder is from SLC and actually stops in Junction] so it never hits the Frange), but FedEx is just a hot mess.
The Henderson facility just north of Denver (FedEx Ground sort for anything in the state, even Western Slope ) is horribly understaffed, and chronically so. Very regularly they cannot process incoming trailers in time, and it isn't physical volume issues, the facilities are big enough, just not enough people willing to work for a company that, to use a friend's parlance who left FedEx for UPS recently "cares more about fueling Freddie's planes and yachts than actually delivering for customers or employees" (take that as what it is: one ex-FedEx employee's quote, that's all), they also rely on a very, very tight air ops schedule for Western Slope service for air services: it's a single 757 that makes a stop in the Springs and continues to Junction, where it doesn't arrive until about 8AM if all goes well, and so that means, unload & sort better be perfect b/c those boxes have a 1hr drive to Montrose, where there's final sort & load, and then everything has to be perfect after that because those trucks aren't leaving until 1030AM anyway.
And, oh, all this is happening at anywhere between 6000ft up to 10000ft elevation in the San Juan mountains, in the winter, too, so, well, you can imagine how this system is basically set up to fail if you even look at it sideways even under ideal conditions, let alone short handed.
You probably have a (bit) better in the Front Range just out of pure density & the physics of distance/space being more favorable in that (and labor wise you might have less of an issue), but they still can't figure out that Henderson operation, it's been a disaster for a few year now, but when they're not willing to keep up with UPS or Amazon's pay for the actual people doing the actual service work, well, I am not surprised...